Electrical terminal for conductive foil

ABSTRACT

An electrical terminal is disclosed that is adapted to be adhesively retained upon a smooth surface such as glass. The terminal contains a flat generally U shaped spring member encircling a cooperating insulator block member. The spring member completes an electrical path to a frangible conductive tape carried by the glass from an electrically conductive wire held in intimate contact with the spring member by screws. The aforementioned Abstract is neither intended to define the invention of the application which, of course, is measured by the claims, not is it intended to be limiting as to the scope of the invention in any way.

United States Patent 1 [111 3,794,953

Malin Feb. 26, 1974 ELECTRICAL TERMINAL FOR CONDUCTIVE FOIL Jack Malin, Beechhurst, N.Y.

Security Instruments, Inc., Bronx, NY.

Filed: Jan. 22, 1973 Appl. No.: 325,562

Inventor:

Assignee:

US. Cl 339/17 C, 174/68.5, 174/117 A, 339/125 R, 339/269 Int. Cl I-I0lr 9/10 Field of Search 339/17, 75, 119, 125, 269, 339/271; 174/68.5, 117 A [56] References Cited UNITED STATES PATENTS 3,444,502 5/1969 Matthews 339/17 C 3,611,249 10/1971 Lovrenich 339/271 FOREIGN PATENTS OR APPLICATIONS 756,758 4/1967 Canada 339/119 R Primary Examiner-Joseph H. McGlynn Attorney, Agent, or Firm--Leonard H. King The aforementioned Abstract is neither intended to define the invention of the application which, of course, is measured by the claims, notis it intended to be limiting as to the scope of the invention in any way.

7 Claims, 3 Drawing Figures H (e W Y Z A ELECTRICAL TERMINAL FOR CONDUCTIVE FOIL BACKGROUND OF THE INVENTION This invention relates to electrical terminals and, in particular, to an electrical terminal adapted to be affixed to a smooth surface such as glass, which provides a complete conductive path from a wire retained on the terminal block member to an electrically conductive frangible tape provided on the smooth surface.

Present day burglar alarm systems are designed to detect essentially all means of entry to a secured premises. Since glass windows and doors are particularly vulnerable to destruction by a person seeking unlawful entry to the premises, these entrances are generally provided with a means for detecting breaking of the glass. The alarm system normally includes an electrical circuit which will activate the alarm if electrical conductivity is interrupted. Conventionally, the glass to be protected is coated with an adhesive backed frangible electrically conductive metallic tape about the circumference of the glass, generally a few inches from the edges thereof. Breaking or cutting the glass causes it to shatter and tear the conductive tape thereby breaking the circuit. The path is generally a series path between all conductive tapes and wires and completes an electrically conductive path to a relay. A break at any point in the series conductive path deenergizes the relay and activates the alarm.

The prior art method of connection to the tape was to solder a conductive wire to the conductive tape after the tape has been affixed to the glass. The wire was then connected to a fixed terminal mounted on the window frame which had another wire affixed thereon connected to the electrical circuitry. Extreme care was required when soldering the wire to the metallic tape in order that the tape not be torn or the window broken. It will be appreciated that this made the installation time consuming, hence costly as well as precarious.

SUMMARY OF THE INVENTION The preferred embodiment of the present invention provides a terminal that may be affixed to a smooth surface such as glass and provides intimate electrical contact with a metallic conductive tape provided thereon, thus, eliminating the need for soldering to the tape or mounting a terminal on a surrounding molding or wall.

An electrical terminal fabricated in accordance with the principles of the present invention comprises in combination, an insulated block member having a top and bottom surface, the top surface having a hole provided therein, an electrically conductive spring member having a hole therein adapted to cooperate with the hole in the insulated block, the spring member encircling the block member and normally extending beyond the bottom surface thereof. The terminal further includes, adhesive means, provided on the bottom surface of the block member, for retaining the block member on a surface and adapted to retain the spring member in intimate contact with an electrical conductor provided on the surface of the glass, and screw means adapted to cooperate with the holes and adapted to complete an electrically conductive path between the wire affixed thereunder and the electrical surface conductor.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing.

DESCRIPTION OF THE DRAWING FIG. 1 is a pictorial representation of a burglar alarm system including an enlarged perspective view of an adhesively secured terminal fabricated in accordance with the principles of the present invention;

FIG. 2 is an enlarged cross-sectional view in elevation of the adhesive spring terminal of FIG. 1 taken along line 22 thereof; and

FIG. 3 is an enlarged cross-sectional view, in elevation, of the adhesive spring terminal of FIG. 1 taken along line 3-3 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, (FIGS. 1, 2 and 3) wherein the numeral 10 generally refers to a burglar alarm system. The burglar alarm system in the preferred embodiment includes a housing 12, within which is incorporated all of the conventional alarm electrical circuit components including a relay, not shown, a siren or bell 11 is connected to the relay. A conventional line cord 14 and a plug 16 which is adapted to be plugged into a source of electrical power, not shown, is coupled to the housing 12 and supplies the electrical energy for the alarm system. Alternatively a battery, not shown, mounted within the housing 12 supplies the energy for the electrical circuitry, should the AC power fail or be disconnected for any reason. Other systems may be solely AC or battery operated. A pair of terminals 18 and 20 are provided on the housing 12 which are coupled to the electrical circuitry within the housing. The electrical circuitry is designed not to activate the alarm system as long as an electrically conductive path is maintained between the terminals l8 and 20.

The burglar alarm system 10 is designed to activate the alarm device such as a siren or hell 1 1, when a protected glass window is broken. An electrically conductive tape 22, which is provided with an adhesive backing 24 is affixed to a glass window 26. The tape is generally affixed about the windows periphery a few inches from each edge. An electrical terminal 28 is adhesively affixed to the glass window 26 straddling the conductive tape as shown in FIG. 1 by an adhesive material 31 carried by a foam pad 30 provided along bottom edge 32 and 34 on either side of a bottom channel 36 of an insulating block member 38. The preferred adhesive material includes a polyurethane foam pad 30 and a pressure sensitive adhesive layer 31 protected by a non-adherent strippable film 33.

Block member 38, in the preferred embodiment, is molded in a unitary structure of an electrically nonconductive thermoplastic material, such as polystyrene, and has sloped or chamfered sides 40 terminating in a flat top surface 42. The top surface 42 is provided with a hole 44 therein. Hole 44 may be threaded to cooperate with a screw 46 or, for added strength, provided with a metal bushing 48 which has threads therein. The bushing member 48 may be insert molded or inserted after block member 38 is molded.

A metal flat or leaf spring member 50 is formed to have a generally U shape and is provided with a hole 52 which is adapted to cooperate with the hole 44 provided in the top surface 42 of block member 38. Spring member 50 is fabricated of an electrically conductive metallic material and encircles block member 38 by extending downwardly within a rear channel 54 (FIG. 2) provided in block member 38 and forwardly within the bottom channel 36 of block 38. Spring 50in its relaxed or uncompressed state extends below the bottom surface of edges 32 and 34. When the adhesive terminal block 28 is affixed to the glass surface the spring 50 is compressed thereby insuring intimate contact with the conducting tape 22.

In operation, an electrically conductive wire 56 is connected from terminal 18 of the housing 12 to the screw 46 of terminal 28. Tightening screw 46 with the wire 56 thereunder, completes the electrical path from terminal 18 to the conductive tape 22. A second terminal, not shown, is applied in the same manner as terminal 28 to the glass at the other end of the conductive tape 22. A second electrically conductive wire 58 is connected from terminal 20 to the other terminal thereby forming a complete electrically conductive path between the terminals 18 and 20. If the glass is broken for any reason the conductive tape 22 would be torn or the adhesive terminal 38 would be removed from the glass, thus, the continuous conductive path between terminals 18 and 20 would be broken'and the alarm would be activated.

Note that, although a single glass window utilizing two adhesive terminals has been described by way of example, any number of windows may be protected by using additional terminals and being certain that a continuous series electrically conductive path is maintained between terminals 18 and 20. A break at any point within the path will activate the alarm.

Hereinbefore there has been disclosed an electrical spring terminal which is relatively inexpensive to manufacture, easy to install and ideally suited for mounting on smooth surfaces such as glass.

There has been disclosed heretofore the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent is:

1. An electrical terminal for being adhesively secured to a surface carrying a frangible conductive strip comprising in combination:

a. an electrically non-conductive block member having a top and bottom surface, said top surface having a threaded bore extending therefrom;

b. an electrically conductive spring member having a hole therein aligned with the bore in said insulated block member,'said spring member encircling said block member and normally extending beyond said bottom surface thereof;

0. adhesive means provided on said bottom surface of said block member for retaining said block member on a surface whereby the said spring member is depressed to a compressed condition and is adapted to retain said spring member in intimate contact with the electrical conductor provided on said surface; and

d. screw means adapted to cooperate with said holes and adapted to complete an electrically conductive path between a wire affixed thereunder and the frangible conductive strip.

2. An electrical terminal according to claim 1 wherein said spring member is fabricated of electrically conductive flat spring material being generally of a U shape.

3. An electrical terminal according to claim 1 wherein said block member is fabricated of a unitary thermoplastic electrically non-conductive material.

4. An electrical terminal according to claim 1 further including a threaded metal insert provided within said insulated block member and adapted to retain said screw means.

5. An electrical terminal according to claim 1 including a foam pad interposed between the said adhesive means and said block member.

6. The electrical terminal of claim 5 wherein said adhesive means is pressure sensitive.

7. The electrical terminal of claim 5 wherein said adhesive means if provided with a strippable protective layer. 

1. An electrical terminal for being adhesively secured to a surface carrying a frangible conductive strip comprising in combination: a. an electrically non-conductive block member having a top and bottom surface, said top surface having a threaded bore extending therefrom; b. an electrically conductive spring member having a hole therein aligned with the bore in said insulated block member, said spring member encircling said block member and normally extending beyond said bottom surface thereof; c. adhesive means provided on said bottom surface of said block member for retaining said block member on a surface whereby the said spring member is depressed to a compressed condition and is adapted to retain said spring member in intimate contact with the electrical conductor provided on said surface; and d. screw means adapted to cooperate with said holes and adapted to complete an electrically conductive path between a wire affixed thereunder and the frangible conductive strip.
 2. An electrical terminal according to claim 1 wherein said spring member is fabricated of electrically conductive flat spring material being generally of a U shape.
 3. An electrical terminal according to claim 1 wherein said block member is fabricated of a unitary thermoplastic electrically non-conductive material.
 4. An electrical terminal according to claim 1 further including a threaded metal insert provided within said insulated block member and adapted to retain said screw means.
 5. An electrical terminal according to claim 1 including a foam pad interposed between the said adhesive means and said block member.
 6. The electrical terminal of claim 5 wherein said adhesive means is pressure sensitive.
 7. The electrical terminal of claim 5 wherein said adhesive means if provided with a strippable protective layer. 